1. Field of the Invention
The present invention relates to the field of display technologies, and in particular, to a method for detecting an etching residue.
2. Description of the Prior Art
During the process of producing an array substrate and a cell substrate, a patterning process is an indispensable step. Generally, the patterning process includes coating of photoresist, exposing, developing and etching. During an etching process, poor etch uniformity will often cause a problem of etching residues, wherein the etching residues refer to some residues existing after the patterning process. In other word, the film layer which should be fully removed is not totally removed.
For example, for a bottom gate-type array substrate, the production process may include: forming a gate, a gate insulating layer, an active layer, a source electrode and a drain electrode, and a protective layer and a pixel electrode in turn on a substrate, wherein the active layer may include an amorphous silicon layer and an n+ amorphous silicon layer, and the pixel electrode is connected with the drain by a via hole provided on the protective layer.
When forming the n+ amorphous silicon layer, the n+ amorphous silicon corresponding to the gap between the source electrode and the drain electrode must be fully etched. However, there usually exists a phenomenon that the n+ amorphous silicon is not fully etched after the etching process, which will cause a structure change of the final array substrate produced, thereby producing degraded products.
Additionally, when forming the via hole on the protective layer, the material of the protective layer at the via hole, such as silicon nitride, also must be fully etched. However, there usually also exists a phenomenon that the material of the protective layer at the via hole is not etched fully after the etching process, which will causes a result that the pixel electrode and the drain cannot be connected via the via hole, thereby producing degraded products.